Hyundai Coupe starting problems

2002 Hyundai Coupe Problem

When I go to start it, the engine hangs on the starter and then splutters into life.
Hyundai say they cant find anything wrong with the car, and are hnappy that this is normal.
I found the spark plugs are quite sooted up, could it be the MAF sensor because I have changed the engine temp sensor and the TPS sensor.